Many battery powered laptop computers weigh less than perhaps 6 pounds (13.2 Kg) and use a liquid crystal display ("LCD") screen. Typically, the laptop computer is contained within a clamshell-like housing, in which a lower housing portion containing the keyboard is hingedly attached to an upper housing portion containing the LCD.
FIG. 1A depicts a generic laptop computer 10 whose lower housing portion 20 contains a keyboard 30 and is coupled via a hinge mechanism 40 to an upper housing portion 50 that includes the liquid crystal display ("LCD") 60. Upper and lower housing portions 20 and 50 are commonly made from a light weight plastic material. Computer 10 further includes a central processing unit ("CPU") integrated circuit 70, random access and persistent storage memory, collectively shown as 80, and a battery 90 that powers the computer.
FIG. 1B is a cutaway topview showing details of prior art mounting of LCD 60 to the upper housing 50. As provided by its manufacturer, LCD 60 normally is attached to a plastic holder 100, and as used herein, the term LCD-assembly 110 shall refer collectively to holder 100 and LCD 60 per se. Damage to LCDs typically results from twisting of display 60 as a result of impact, falls, and the like. To minimize such twisting and damage, LCD assembly 110 is mounted to a rigid metal plate or shield 120, with screws 130. Metal plate 120 is commonly aluminum or steel.
Metal plate 120 in turn is mounted by screws 150 to the rear portion 140 of upper housing 150. Commonly, the front-facing portion 160 of upper housing 150 is joined to rear portion 140, and forms a frame about LCD 60.
Unfortunately, when the laptop computer is dropped or otherwise sufficiently severely stressed, upper housing 50 flexes, causing failure at screw(s) 150. As a result, metal plate 120 will flex, transferring the stress load to LCD assembly 110. The transferred stress, if sufficient in magnitude, twists and damages LCD 60. Such LCD damage can be reduced by adding to the strength of the upper housing 50, by providing a more rigid metal plate 120, by providing more mounting screws 150 and 130, and by providing a stronger LCD plastic holder 100, or any combination thereof. Unfortunately, implementing these options adds to the weight of the laptop computer, and can also increase the time and cost associated with assembly of the laptop computer.
In the past, LCD screens 60 commonly measured 9.5" (24 cm) diagonally. However, in an attempt to provide a larger, more readable and useful display, 10.4" (26 cm) screens are now used, and it is expected that 12.1" (31 cm) screens will soon become commonplace. Further, there is a trend away from the earlier monochrome LCD screens to more costly but easier to view passive and active color LCD screens.
Whether active or passive, a color LCD is costly and can represent a substantial portion of the manufacturing cost of the entire laptop computer. For example, a 10.4" (26 cm) active color LCD represents more than 75% of the total cost of the laptop computer. These screens, especially the larger sized screens, are vulnerable to breakage if the laptop computer is dropped or is otherwise mechanically stressed. If the LCD is damaged, as a practical matter the user-owner will probably replace the laptop computer outright rather than incur a nearly equal expense merely to replace the broken screen.
From the user's point of view, what is desired is a lightweight laptop with a large, active color LCD. However the prospective cost to replace the laptop computer in the event of LCD breakage causes many users to purchase laptops with smaller sized screens, or even with relatively inexpensive monochrome LCD screens. From the manufacturer's point of view, such purchase decisions are undesired because it is more profitable to produce and sell large-sized active color LCD laptops. Large-sized active color LCD laptops are also preferred from the software programmer's point of view, as such screens can more readily display more icon graphics, menus, and the like.
In an attempt to ruggedize the laptop computer, some manufacturers provide a housing 20, 50 made from metal, e.g., die cast magnesium. Metal enclosures can help protect the laptop and LCD screen from damage while the computer is stationary, e.g., from stress damage resulting from a heavy object placed atop the closed computer. However, if the computer is dropped, the additional weight and momentum resulting from the metal housing can actually increase the likelihood of LCD damage. Further, the additional weight and expense contributed by the metal housing makes the computer less desirable to consumers, who prefer lightweight, inexpensive, laptops.
Many manufacturers use plastic housing portions 20, 50, and stiffen the LCD-containing upper housing portion 50 using ribs or a stronger plastic. While less expensive than a metal housing, the resultant reinforced structure still adds weight to the laptop computer. For example, a rib-reinforced plastic-housed laptop computer with a 10.4" (26 cm) LCD weighs 5.5 about pounds. (2.5 Kg).
What is needed is a structure and method that decreases laptop computer weight, while providing a housing that better protects the LCD without incurring substantial manufacturing costs. Preferably, such housing should provide greater protection than present techniques, while simultaneously providing a weight savings.
The present invention discloses such a structure for a LCD laptop computer.